It's been a long time since I last played Punch-Out. This is a neat clone of it. I like the fantasy theme. From what I could see the core mechanics look to be good. Unfortunately, I had trouble actually playing the game. The left click was very unreliable. Sometimes, especially at the start, it would work, but then it was being ignored. I am aware of the limited energy for attacks, and even when I had energy and should have been able to attack I was not able to do so. I could move with WASD, and right-click activated the block. I pressed F12 to see if I could find anything in the console, and that activated the mobile controls. I was then able to defeat the first boss by using WASD for movement and clicking the on-screen "A" button for my attacks. I saw that there was supposed to be a chargeable attack by pressing "S" and left click. I never saw any indication that things were charging up from this, including with using the mobile button. It would also be nice if there was an indication of when you switch between high and low. Nothing visible seemed to change when I pressed the button, though looking at the console I do see it reporting that the state changed.
I am playing with the Vivaldi browser (Chromium based), on Linux, so it is possible some of the input issues are from the browser or OS.